1. Field of the Invention
The present invention relates to a method for extending a switching matrix of a communication system without interruption, wherein the switching matrix has a number of switching matrix assemblies via which a number of cell streams having ATM cells are routed as stipulated by a routing address placed in front of a cell header, and the routing address taking up a prescribed memory space requirement.
2. Description of the Prior Art
Generally, the switching matrix can be regarded as the central part of a communication system. The switching matrix has a number of assemblies through which the information for all the connections is routed. If the connection capacity of a communication system is to be extended, the switching matrix, as central part, needs to be enlarged in particular. This is particularly true, also, for switching matrices which connect and transmit information packaged in ATM cells.
Contemporary ATM switching matrices are extended by replacing the old switching matrix components with new components. Extension in terms of adding new components to the old components in modular fashion, with the old components being able to be used as previously, is carried out only rarely. The switching matrix therefore generally needs to be completely restructured.
This has consequences both for the operating system and for the path information of the ATM cells which are to be connected. In particular, the routing addresses which show the path to the ATM cell within the switching matrix need to be changed appropriately once the switching matrix has been changed over. During operation of the switching matrix, this cannot be done, or can be done only with great complexity. In the case of this prior art, to extend the switching matrix, operation is therefore interrupted and the switching matrix is completely disconnected. This then allows the switching matrix to be changed over and the routing addresses to be changed.
The document “A Scalable ATM Switching System Architecture”, Wolfgang Fischer et al., IEEE Journal of Selected Areas in Communications, 9(1991) October, No. 8, New York, US discloses the architecture of an ATM switching system. Specific measures to be taken in order to add equipment to the switching matrix of the ATM switching system during ongoing operation are not addressed in this case, however.
In addition, US patent specification U.S. Pat. No. 5,325,089 likewise discloses an extendable ATM switching matrix. The extension is described here in detail within the context of how the individual stages need to be wired together. Specific measures to be taken in order to add equipment to the switching matrix of the ATM switching system during ongoing operation without any great complexity are also not addressed in this case.
The present invention is directed to demonstrating a way in which switching matrices can be extended without disrupting operation.